Could the OPDA be the source of my oil leak?

mgroeger

mgroeger

TJ Enthusiast
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Aug 24, 2018
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Location
Hurricane, UT
Background...
2004 LJ 4.0L automatic
Just put a new ATK engine in the Jeep and there is a significant leak at the OPDA/Cam shaft positioning sensor.
My first assumption was the thin paper gasket wasn't doing it's job so I bought the Mopar one which clearly was a better gasket. I took the top sensor off and took a picture of the position of the OPDA to make sure I got it back the right way. I put the new gasket on and tightened everything down, engine fired right up and ran smoothly. Took it for a spin and it leaks even worse now.
As I examined it I saw that there was oil up the side of the OPDA. I thought that was odd since the gasket is at the base, then I remembered that I saw oil up under the sensor when I pulled it off (but not a lot). My thoughts now are that the actual OPDA is bad and somehow allowing oil to come out of the top and run down the side of it. Is that even possible??

Questions:
- If it is possible for that unit to be the source of the leak what should I replace it with? Dorman? Crown? Mopar?
- I am assuming I got it back in right since it ran smoothly. What does it look/sound/run like if you get this thing off from where it should be? Will it throw a code? I don't want to assume I have it installed right just because it is running smoothly.

Side note, I did order the Mopar camshaft positioning sensor and will be installing that as well.

Any other wisdom would be greatly appreciated. After dropping over $3k on this engine, extra parts and install I'm a little on edge with anything like this coming up.
 
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After doing some research I can't even find a OPDA for a 2004. You can't throw a stick without hitting one for a 05-06 though.
 
mgroeger said:
After doing some research I can't even find a OPDA for a 2004. You can't throw a stick without hitting one for a 05-06 though.
Click to expand...

@MX952, is it still referred to as the OPDA on 2004 and earlier models? And did you ever confirm 100% as to whether they are interchangeable or not? I know you were researching this.
 
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Chris said:
They can indeed leak oil from what I understand.
Click to expand...

I thought of an experiment. When driving this oil is getting migrated all over the place so I'm going to clean it really good and then let it idle in my driveway for however long it takes to leak and then pinpoint the leak.

Do you have any insight as to this?
- I am assuming I got it back in right since it ran smoothly. What does it look/sound/run like if you get this thing off from where it should be? Will it throw a code? I don't want to assume I have it installed right just because it is running smoothly.
 
mgroeger said:
I thought of an experiment. When driving this oil is getting migrated all over the place so I'm going to clean it really good and then let it idle in my driveway for however long it takes to leak and then pinpoint the leak.

Do you have any insight as to this?
- I am assuming I got it back in right since it ran smoothly. What does it look/sound/run like if you get this thing off from where it should be? Will it throw a code? I don't want to assume I have it installed right just because it is running smoothly.
Click to expand...

@taylormade73 might be able to answer that.
 
I have an 06 with opda, theres 2 places it might leak, the first one is where the opda actually mates with the block. If theres no gasket, or its bad it will leak there. The second place is the actual cup, oil might go up and down through the hole in the cup. I have the crown opda relacement.

The jeep would not start if its badly oriented
 
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There is a tolerance of a few degrees off, but as Blaine said, there is enough play that if you are on the edge either way of the tolerance, then it can throw the code P0016. Too far off it won't start or stay running, but it can be slightly off and run/idle roughly or run seemingly fine to the human eyes and ears. Mine was slightly off but I was at the edge of the tolerance so it eventually threw a code after several miles and hours of driving. I ran through the TDC sequence again and readjusted the OPDA and apparently got lucky and got it right the second time. I drove all day today over 100 miles and everything was fine. With that said, I'm still going to take Blaine's advice and have someone with a DRB set it exactly so that I know its right. In my experience it can be off and run seemingly fine with no code.
 
Chris said:
@MX952, is it still referred to as the OPDA on 2004 and earlier models? And did you ever confirm 100% as to whether they are interchangeable or not? I know you were researching this.
Click to expand...
The pre-2005-2006 is called the cam synchronizer. As for if they are compatible...I still haven’t found anyone to check live voltage to compare the older versus newer.

Still not confirmed I guess is the answer.
 
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MountaineerTom said:
Just curious, what is a DRB and what does it do?
Click to expand...
I believe a diagnostic readout box. You would use it to read the signal from a sensor while adjusting/fine tuning whatever the sensor is monitoring, which in this case would be reading the CPS regarding the timing of the crankshaft and camshaft amd adjusting OPDA alignment.
 
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taylormade73 said:
I believe a diagnostic readout box. You would use it to read the signal from a sensor while adjusting/fine tuning whatever the sensor is monitoring, which in this case would be reading the CPS regarding the timing of the crankshaft and camshaft amd adjusting OPDA alignment.
Click to expand...

Ahh, ok, thanks.
 
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Game plan as of now is to replace the entire unit and sensor on the top. I already have the sensor and bought the official Mopar one for $51. The Crown OPDA is $73 from Quadratec and I will order that today. Something is clearly leaking there and I didn't just drop over $3k to fiddle fart and cut corners on a $75 part. Hopefully will be here by end of week so I can off road at our local spot before it closes for the season.

Replacing this engine has been an incredible learning experience.
 
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